The invention relates to a refrigeration circuit having a mono- or multi-component refrigerant circulating therein, said circuit comprising, in the direction of flow, a condenser, a collecting container, a relief device connected upstream of an evaporator, an evaporator and a compressor unit with single-stage compression.
Furthermore, the invention relates to a method of operating a refrigeration circuit.
The term “condenser” is to be understood to comprise both condensers and gas coolers.
Refrigeration circuits of the type concerned are well known. They are realized, for example, in refrigerating plants, so-called composite refrigerating plants, as used in supermarkets. In general, composite refrigerating plants feed there a multiplicity of cold consumers, such as cold storages, refrigerating and deep-freezing furniture. To this end, a mono- or multi-component refrigerant or refrigerant mixture circulates in the same.
A refrigeration circuit or refrigerating plant according to the prior art, realizing such a refrigeration circuit, shall be elucidated in more detail by way of the example illustrated in FIG. 1.
The mono- or single component refrigerant circulating in the refrigeration circuit is condensed in a condenser or gas cooler A—in the following briefly referred to as condenser only—which as a rule is arranged outside of a supermarket, e.g. on the roof thereof, by exchange of heat, preferably with respect to outside air.
The liquid refrigerant from the condenser A is supplied via a line B to a (refrigerant) collector C. Within a refrigeration circuit it is necessary at all times that sufficient refrigerant is present so that also in case of maximum refrigeration requirements the condensers of all cold consumers can be filled. However, due to the fact that in case of lower refrigeration requirements, some condensers are filled only partially or even are completely empty, the surplus of refrigerant during these times has to be collected in the collector C provided therefor.
From the collector C, the refrigerant passes via liquid line D to the cold consumers of the so-called normal refrigeration circuit. In this regard, the consumers F and F′ depicted in FIG. 1 stand for an arbitrary number of consumers of the normal refrigeration circuit. Each of the afore-mentioned cold consumers has an expansion valve E and E′, respectively, connected upstream thereof, in which pressure relief of the refrigerant flowing into the cold consumer or the evaporator(s) of the cold consumer takes place. The thus pressure-relieved refrigerant is evaporated in the evaporators of the cold consumers F and F′ and thereby refrigerates the corresponding refrigeration furniture and storage rooms.
The refrigerant evaporated in the cold consumers F and F′ of the normal refrigeration circuit then is fed via suction line G to compressor unit H and is compressed therein to the desired pressure between 10 and 25 bar. As a rule, the compressor unit H is of single-stage design only and has a plurality of compressors connected in parallel.
The refrigerant compressed in the compressor unit H then is fed via pressure line I to the afore-mentioned condenser A.
Via a second liquid line D′, refrigerant is fed from collector C to condensing means K and is evaporated therein, exchanging heat with the refrigerant of the deep-freeze circuit still to be elucidated, before it is supplied via line G′ to compressor unit H.
The refrigerant of the deep-freezing circuit liquefied in condensing means K is supplied via line L to the collector M of the deep-freeze circuit. From the latter, the refrigerant is passed via line L to consumer P—which stands for an arbitrary number of consumers—having a relief device O connected upstream thereof, and is evaporated therein. Via suction line Q, the evaporated refrigerant is fed to the single-stage or multi-stage compressor unit R and is compressed in the same to a pressure between 25 and 40 bar and thereafter is supplied to the afore-mentioned condensing means K via pressure line S.
The refrigerant used in the normal refrigeration circuit is e.g. R 404A, whereas carbon dioxide is utilized for the deep-freeze circuit.
The compressor units H and R shown in FIG. 1, the collectors C and M as well as the condensing means K as a rule are disposed in a separate machine room. However, about 80 to 90 percent of the entire line network are arranged in the sales rooms, storage rooms or other rooms of a supermarket that are accessible to staff members and customers. As long as this line network does not make use of pressures of more than 35 to 40 bar, this is acceptable to the supermarket operator both under psychological aspects and for reasons of costs.